"This was a very tough decision for me and my family, but it's now the right time for me to bring my career with the Baltimore Police Department to a close," Bealefeld said in a statement released by the mayor's office. "I am looking forward to enjoying retirement with my family and close friends."

A senior aide to the mayor told the 11 News I-Team Thursday that Bealefeld will retire as of Aug. 1.

The aide said the mayor is saddened by the choice but respects Bealefeld's decision. A national search will be conducted to find a replacement, the aide said.

"I know he loves the job and was proud to serve with honesty and integrity for these many years. He has been an extremely effective leader that we will miss, and we wish him the best retirement," Mayor Stephanie Rawlings-Blake said in a statement.

Bealefeld has served as the city's police commissioner since then Mayor Sheila Dixon appointed him on Nov 20, 2007.

"I thought, at least externally in the crime-fighting, I thought the department was doing well. Administratively and internally, they had their issues, and it was becoming more and more difficult," said Gary McLhinney, former chief of the Maryland Transportation Authority Police Department.

He is credited with achieving significant drops in the city's notorious homicide numbers, and he's well known for his candid straight-talk, using phrases like "bad guys with guns" and often referring to criminals as "knuckleheads."

"I liked his no-nonsense approach to the job that he held," said Maryanne Reynolds, a city resident. "I think he has really started moving Baltimore in the right way."

Bealefeld has said that he has "made it his mission" to root out corruption within the Police Department. On his watch, Bealefeld has had to deal with stains on the department's reputation, including a towing scandal last year, the conviction last month of an officer who sold heroine while on duty at a city police station and allegations this year about a rogue investigation organized by a suspended homicide detective who led the investigation into the death of Phylicia Barnes.

"It sure is a burden that distracts a police department from its mission," McLhinney said. "Whether the public has confidence in the police officers and the Police Department to do its job, it really is a big distraction when you have these types of issues that aren't being dealt with, or that keep coming up repeatedly over time."

"He came in on a mess, and he did his best to straighten (it) out the best he could," said Alice Blackwell, a city resident. "He helped the police, he helped the citizens. So, I'm sorry he's leaving."

Bealefeld is credited with reducing gun violence and homicides in Baltimore to the lowest levels since the 1970s. As commissioner, Bealefeld made it a priority to focus on violent offenders and improve relationships between police and the community.

Under Bealefeld's tenure, the Police Department achieved double-digit declines in gun crime and has benefited from the creation of a gun offender registry. Bealefeld is known as a strong advocate for tougher penalties for gun offenders.

Since 2007, overall gun crime dropped by 24 percent, and, according to the mayor's office, the city recorded the fewest number of homicides in 35 years last year.

Bealefeld began his Baltimore police career as a cadet in 1981, patrolling west Baltimore neighborhoods. He has served in almost all operational units of the department before his appointment to commissioner in 2008.

Bealefeld's announcement comes on the heels of other departures at City Hall, including that of Sheryl Goldstein, who announced Thursday that she is stepping down as director of the Mayor's Office on Criminal Justice.